Multifunctional, hand-held tool machines include, but are not limited to, for example, circular saws, orbital sanders, vibrating grinders, drills or impact drills, as well as combination hammers, which are converted over from a drilling to a chiseling operation. It is understood that the latter type of equipment is an example and is not meant to limit the universal applicability of the invention described herein.
In combination hammers, when the drilling operation is selected, a tool and its holding head are driven to rotate with or without impacting. On the other hand, when the chiseling operation is selected, the tool, that is, the chisel is driven exclusively forwards and backwards to impact. The respective tool is changed over from one type of operation to the other type of operation by rotating a switch mounted at the housing or by shifting a switching key between at least two switching positions. Usually, drilling hammers belong to a class of equipment, which requires a relatively high driving power. In drilling operations, in order to prevent rotation accidents because of blockage of the tool, for example, when it hits iron, due to the reaction moment acting on the housing of the equipment, such tool machines contain means for determining the relative angle of rotation of the housing associated with the driving electronics of the integrated circuit. If the angle of rotation at the housing exceeds a certain value within a short time span of a few milliseconds because the reaction moment has increased suddenly as a result of the blockage of the tool, the drive line between the motor and the tool holder is interrupted by a rapidly acting coupling. Examples of such devices for monitoring the reaction moment are described in detail in the publications WO 88 06 508 A3, DE 43 44 817 C2 or EP 0 686 148 A2 and DE 196 41 618 A1.
If the user selects a different mode of operation, such as the chiseling operation, there is no danger of rotation accidents, since the tool is no longer driven rotationally. The individual electrical system functions must therefore be set differently for the chiseling operation than for the drilling operation. In particular, an unmotivated switching-off of the combination hammer is undesirable since it would unnecessarily slow down the working process. This is particularly true for certain application cases and courses, for which a sudden rotational movement of the tool machine is unavoidable, for example, when dressing the edges and borders of concrete constructions and when breaching walls with a chisel and the like. In other words, when the chiseling operation is selected, the electrical system function of the time-dependent rotation angle monitoring and, if necessary, interruption of the drive line should be switched off and/or individual operating parameters of the tool machine should be switched over.